There are two existing I.E.E.E. Standards for linear electrical data busses numbered 802.3 and 802.4. The difference between the two is the protocol and not the electrical bus interface. There is no available simple way to add optical terminals to these existing busses. There is such a need. In addition there is a need for both optical bus-to-bus transmissions, and optical-to-electrical and electrical-to-optical bus-to-bus transmissions.
In the field of linear data busses where fiber optics are employed it has been known to use fiber optics to connect terminals. U.S. Pat. No. 4,837,856, issued to Andrew Glista on Jun. 6, 1989 disclosed a fault-tolerant fiber optic coupler/repeater for use in a terminal in a high speed digital, audio or video (sometimes called a multi-modality) data transmission system which has an optical data input from one or a plurality of upstream terminals and which sends optical data to one or a plurality of downstream terminals via fiber optic lines. There is a bypass line which allows for a bypass of one or more upstream terminals.
U.S. Pat. No. 4,845,722 to Allan R. Kent et al, issued Jul. 4, 1989 disclosed a computer interconnect coupler which has a set of junctors which are assigned to channel transmitters and channel receivers for routing of messages from the channel receivers which are addressed to the channel transmitters. This computer interconnect coupler employed crossbar switching. A pair of interconnect couplers was provided which were linked together to ensure a mutually consistent definition of a virtual star coupling as well as to share diagnostic information. The patent does not disclose a fiber coupling or any way to allow a "virtual star coupling" to be accomplished by a fiber optic connector in a modular fashion.
Fiber optic circuitry has been employed in a number of specific ways. U.S. Pat. No. 4,511,207 to Steven A. Newton et al issued Apr. 16, 1985, proposed the use of a fiber optic data distributor with a one-by-n single mode optical fiber directional coupler to distribute data from a single fiber to a plurality of separate fibers. U.S. Pat. No. 4,479,701 to Steven A. Newton et al issued Oct. 30, 1984, disclosed a fiber optic recirculating memory which used dual couplers to form a splice free recirculating memory device from a single mode optical fiber much in the way delay line memories were formed during the early days of computer development. U.S. Pat. No. 4,451,916 to Paul W. Casper et al issued May 29, 1984, proposed a repeated, multi-channel fiber optic communication network for the use of fiber optics as a plurality of full duplex optic channels and one or more auxiliary channels for fault isolation. The system was intended for use in voice/digital data transmissions across the telephone network.